• Interactions among living things and with their nonliving environment create an ever-changing ecosystem
• Each part of a system is important for the working of that system
• In ecosystems, there are both living and nonliving components
ecosystem - an area in which living and nonliving things interact (An oak tree and the organisms that inhabit it can be thought of as a small ecosystem.)
community - all the organisms living together in a particular ecosystem (Raccoons, deer, and trees are part of a forest community.)
population - a group of the same kind of organisms that live in an area (There is a huge population of frogs in that marsh.)
biotic factors - living (and once living) things in an ecosystem. Ex: trees, birds, insects, etc...
abiotic factors - non-living things in an ecosystem. Ex: soil, rocks, rain, snow, temperature
producer - an organism that makes its own food through photosynthesis (Plants and algae are examples of producers.)
consumer - a living thing that obtains energy by eating other living things (Mean eaters and plant eaters are consumers.)
decomposer - a living thing that breaks down the remains of dead organisms (Decomposers, such as bacteria, get their energy from the dead plants and animals they break down.)
herbivore - a consumer that eats only plants or other producers (Panda bears are herbivores that have a very limited diet because they only eat bamboo.)
carnivore - a consumer that eats only other animals (Lions are carnivores that prey on zebras and other large plant eaters.)
omnivore - a consumer that eats both plants and animals (Because they eat both meats and vegetables, many humans are omnivores.)
parasitism - a relationship between two organisms which one organism lives on or in the other, feeds upon it, and usually harms it (The way in which fleas live off dogs is an example of parasitism.)
commensalism - a close relationship between two kinds of organisms that benefits one of the organisms while neither benefiting nor hurting the other (The way that some insects use their resemblance to plants to hide from predators is an example of commensalism.)
mutualism - a close relationship between two or more organisms in which all organisms benefit (Bees carrying pollen from flower to flower as they obtain nectar is an example of mutualism.)
What is an ecosystem?
Read "The Nature of an Ecosystem"
Complete p. 186
How are living things in an ecosystem related?
Read "The Sun: Life's Energy Supply"
Read "What's to Eat?"
Read "Eat or Be Eaten"